One Of Tasmania's Major Undersea Internet Cables Will Be Cut For Over A Month

The major Basslink undersea power and communications cable that connects Tasmania to the Australian mainland will be cut until mid-March, while the company investigates and fixes a failure in its electricity transmission capacity. That'll leave Tasmanians with severely reduced connectivity to the internet for nearly six weeks, although contingencies are in place.

Basslink doesn't disclose the capacity of the 300km-long undersea cable, although it's understood that several major ISPs including TPG, Internode and iiNet have ongoing deals to use the Basslink cable to service residential and commercial customers in Tasmania. According to Cablemap, the 640Gbps Basslink cable carries the vast majority of Tasmania's internet access to the outside world; the two competing Telstra cables have only 2.5Gbps capacity each.

The cable was damaged in December, and a repair crew on the specialist cable vessel Ile de Re will work to debury the cable from the sea floor and repair it at ground level, after identifying the fault region. The vessel itself required some modification to support the heavy electrical cable; that work was carried out in Geelong.

Basslink Telecom says that the internet service providers that use the dark fibre on its cable for backhaul and connection to the mainland have had to make alternative arrangements for their end user customers. A representative told Gizmodo: "Basslink has contingencies for issues with elements of the land based cable, however none is in place for the undersea component.

"Despite best efforts, a suitable commercial agreement could not be reached between Basslink and Telstra, the owner/operator of the other two subsea fibre optic cables [supporting Tasmania]. Rather, our customers have either put in place or are in the process of doing so, there own contingency arrangements."

Freelance journalist Jason Imms said that when he contacted Internode, his ISP, he was told that "probably... none" of its customers would be affected by the outage, with contigencies put in place. Those contingencies would almost certainly rely on Telstra, which operates two 240km-long Bass Strait 1 and Bass Straight 2 telecommunications cables to Inverloch and Yanakie on the Victorian coastline. iiNet's network map shows this as backup capacity.

Internode is supplying some of its customers affected by the outage with backup wireless solutions. According to the Internode customer support representative, "wireless isn't a great product, but there isn't much we can do about it." The company doesn't list any outages or imminent advisories on its network status website, and other ISPs are similarly quiet on the potential issue.

Whirlpoolcommenters in Tasmania are looking for answers from their ISPs, but no official comments have yet been made. At the moment, the cable repair crew is targeting a completion date of 19 March — that'll be the time that Tasmania's internet connectivity to Australia and the rest of the world returns to normal. "Basslink’s anticipated return to service date remains unchanged at 19 March 2016.

"Contingencies have been built into this timeframe, and there is a possibility that the interconnector may be operational ahead of the indicative date. Despite confidence in our ability to meet the dates, there remain a number of aspects beyond Basslink’s control. We are using best endeavours to work with our partners in a tough environment to meet expectations."

The 4800km APX-Central cable that will be the fourth point of connection between Tasmania, Sydney, Melbourne, Adelaide and Perth is slated for completion in the third quarter of 2016.

Basslink also carries significant power to Tasmania, leaving the island to rely on its own hydroelectric, wind and gas power stations in the interim. The initial fault was with the electricity transmission cable, and the extra weight of that alongside the comms element is partially responsible for the delay.

Basslink does not yet know the cause of the electricity outage. "At this stage, it is too early to speculate." [Basslink]

Comments

Well that sounds less then Ideal. So as I understand it there are 3 cables across the bass straight with a total of 645Gb/s, which will soon drop down to 5Gb/s and ISP's don't expect much of an impact on customers. WOW.

Lets do some maths. Tassie has a population of about half a million. Lets be generous and say an average household has 4 people that means 125000 households in the state. Now lets be generous again and say only 10% have ADSL or NBN connections. That's 12500 connections. 5000Mb/s / 125000 = 0.4Mb/s. Time to get out your dialup modems people.

And that doesn't even take into account businesses and special connections that aren't allowed to go down.

This is a colossal screw up. I don't even.......................................... wth!

It's not misleading. The cable you're looking at that connects Perth, Adelaide, Sydney, Hobart and Melbourne is APX-Central, which won't be active until later in 2016. If you click the cable on the map you linked, it actually says RFS (Ready For Service) Q3 2016. Until then, the only cables are Bass Strait 1, Bass Strait 2 and Basslink.

I hope that in hindsight they could see that this data cable should have been laid separately.
Also the Wikipedia on Basslink shows that for fours at time very high DC flow can be forced thru the interconnector. So maybe it got cooked due to heat build up.

What they were saying on the ABC the other day is that Telstra own the two original cables and ate generous enough to give other companies 5% of capacity on them. Most of the non Telstra traffic uses basslink.

It's another reason the infrastructure shouldn't have gone with Telstra when Johnny sold it off.

On the story, why the heck isn't redundancy built into the system architecture, ya-know, when laying one critical power/comms link, just lay 2. I know it is expensive upfront, but infrastructure projects have a habit of being under-built for future demand.

Not as if the bass straight is a huge gap to bridge or something, it isn't the North Atlantic. (And that has many glass optics (sic) laid across it)

Because if you lay two in the same place then most likely whatever damaged the first one would damage the second also. Complete waste of money to run two parallel submarine cables that start and end in the same place. You would just run a higher fibre count in one cable.
P.S. there is redundancy, there are always more than two alternate paths from any major connection point.

With the power connection - there is redundancy. The backup system is the on-island hydro generation. The backup to that is a gas fired power station.

Unfortunately - Hydro ran the dams flat out in the final year of the carbon tax, to make a huge profit selling to Victoria. They then sold off parts of the gas fired station, because they wouldn't need it because of Basslink. That was then followed by a drought which meant the water storages didn't grow as quickly as expected, followed by the Basslink outage. Yeah, not good.

The backup to the fibre is twofold. First, note that the fibre was laid with the power for internal monitoring reasons - commercial usage was more or less an afterthought.
It is buried under the power cable, so anything physically damaging the cable is going to get the power first. In the example in this article, the fibre outage is scheduled, giving customers time to make alternative arrangements. The second backup is the Telstra cables system (two cables). Unfortunately this means a redundant system has to use Telstra in some form, and they price their services accordingly.
A better form of redundancy will be in place when the APX-Central fibre is laid (or rather, "if" it is laid - Tassie Government still hasn't signed up) There will then be 4 (or 5, if you could Hobart-Perth and Hobart-Sydney as separate systems) routes out of the state across three companies..

Not 3. Maybe 3 pairs (i.e. 6 fibres). Certainly not bundles. And with cladding, buffer, and coloured jacket, you will probably be looking at 0.25-0.5 of a mm or so thickness or thereabouts.

A pair is required, one for transmitting in each direction, as each fibre strand also has many amplifiers (which only work in one direction) spliced in-line with it along the length of the cable maybe every 80km or so. But all these amplifiers have to be housed, and theres only so many you can fit inside the housing which limits the number of pairs you can use. So you might find a typical modern cable with up to 4 pairs, each pair capable of transmitting 10's of individual wavelengths which builds up the cable capacity to the extraordinary figures we hear of.

Assuming we are talking about a "typical" submarine cable that spans oceans of course. It is possible to span distances of 200km or so without any inline amplifiers.

Just talked to him again. Three to six individual fibres (we're talking the one for Australia), signal goes up and down on the fibres and not one for one way and one for the other.(that's how copper line works, not fibre). And the signal does not get boosted along the way. It jumps from country to country and only when the cable is inland that it gets reboosted.

It is possible to get optics that transmit and receive over a single fibre strand, they are referred to as "bidirectional", in Cisco speak they are "BX" optics. But the signal cannot be amplified unless each wavelength is broken out and amplified in its respective direction.

For cable systems, especially ones that span oceans, they are absolutely amplified ("repeated") along the way, and use one fibre for transmitting in each direction. Optical signals are attenuated in fibre just as electrical signals are attenuated in copper. Eventually the signal needs to be amplified, and usually thats 80-100km or thereabouts. You cant span an ocean without amplifying a signal, its physically impossible. Optical fibre is incredibly low loss compared to copper, but it is not lossless.

In the early days of telegraph cables they used various methods to extract an incredibly weak signal from the end of the cable as they didn't have the technology to amplify mid span. But telegraph cables had limitations for the volume and speed of information that could be transmitted across them with these weak signals as a result.

The Pipe International (PPC-1) blog is a good source of information regarding submarine cable construction and covers a lot of topics. Theres also plenty more available elsewhere on-line to confirm it all.

Ah........ No.
Three fibres could possibly transmit a hell of a lot of data but not all of our internet, generally new submarine cables have up to 12, I've seen some as high as 72 but could possibly be even higher for shorter runs. Most of the thickness of the cable is made up of armor sheath for protection and copper wire to power the repeaters required to boost the signal across long expanses. I believe Australia to King Island held a record for one of the longest single spans without a repeater for a while with a 5W laser at one end.

Well that's what our teacher was saying in our NBN course. Tried to Google it but could not find out any info about how many fibres are in it. Oh, and thank you about mentioning the repeaters knowing the signal needs to be boosted down the line. Currently doing a course so I can work in the NBN and it looks like there will be bugger all fibre to work on. Thanks to the liberals.

This is why there should have been redundant link built a long time ago....

Thankfully new link/s are being built for Telecomms side of things. (dont know about power).

Why they haven't built a Long range Point to Point LInk Wireless &/or Microwave (6ghz?) is beyond me. There are plenty of examples of it being done out there just would need alot of them to get large enough capacity...

6ghz p2p over bass straight? You're dreaming right? On a serious note. Over that range you're battling the curvature of the earth. You need to use lower frequencies than 6ghz or so I've been told You need 2 really high points. Currently there are plans by a private company to get a link to Flanders Island. From there you could possibly get to Vic. They're not expecting much bandwidth, maybe 50Mbit full duplex. This is using antennas that are over 2m in diameter. Not many locations in tassie suitable for the link, again, not many suitable locations on the island.

There used to be wireless links over Bass Strait (the first fibre optic link was only built in 1995). One went via King Island to Cape Otway, and one via Flinders Island to Wilsons Promontory. The capacity was pretty low as you may expect!

Now as for what you could achieve with today's wireless tech.. who knows.

I dont believe this APX central cable is going to be built. look at their website, The last news update on their website was a in 2014 and this mob likes to talk themselves up, so i dont believe they have made any progress since. Tassie will be stuck with the 3 current cables for the forseeable future.

Thanks Campbell. A good summary of an aspect of the Basslink break that hasn't got much coverage so far. It's not explicit in you article but I presume that the fibre failed on 20 December at the same time as electricity connection was lost. I'm surprised we are not feeling more pain if we have dropped from 645 to 5 Gbps. Alternative explanation is that fibre is still in operation but will be lost when the cable is cut to repair the electricity break.

It is true that they have to cut the whole cable to repair the electricity conductor. What I am unclear about is whether anyone can confirm that the fibre optic is currently down and if so how are we surviving if our connection has dropped from 645 to 5 Gbps. I am with iiNet and have watched a lot of Netflix since 20 December with only minor glitches.

Fibre is not down at the moment. It will be cut next week. Telstra customers of any type will apparently not see any change (apparently even their nbn goes across their own fibre). So says my work account rep

640G is probably a design limit, at the time, for the Basslink cable. That means they can light up to 640G with the equipment of the time, probably more these days with modern equipment. Actual lit capacity is probably significantly less than 640G.

Telstra is also highly likely to have more than 5G today.

And these cables don't act as one big "connection", they operate significantly differently to what you might be used to. This is not like changing from 1G to 100M ethernet at home.

First off each fibre pair will carry a number of wavelengths of light, one fibre for one direction, the other fibre for the other direction. Next, each wavelength of light can carry 1 or more circuits depending on the type of equipment used. For a single circuit you're talking about a transponder. You take, for example, a 1310nm or 1550nm signal from an ISP, or enterprise or whoever, and re-transmit it on to the cable as a C-band wavelength, somewhere between 1525–1565nm (usually). At the other end you receive that C-band signal, and re-transmit it as a 1310 or 1550nm towards the customer.

Or, you take a "multiplexing transponder" (or muxponder) and multiplex multiple circuits from potentially multiple different customers, re-transmit them as a combined signal in the C-band on to the cable, receive at the other end and de-mux them, and re-transmit each individual original signal towards their respective customers.

Each ISP or other type of customer buys a little "slice" (if you will) of the total available capacity. It could be a wavelength, or it may be a circuit, probably multiplexed if its a lower speed circuit. They can use that how they want, congest it or not, and it wont affect other users of the cable because they have their own dedicated little "slices". One customer does not interfere with another.

It wasn't so much that Basslink decided they only needed one - it was just laid with the power cable for SCADA (internal use only for monitoring the power cable). Commercialisation was more of an afterthought.

I think more the issue is we aren't connected to the national power grid. Dam levels are down (collectively) to 18.9% (even after the rains we've had) and levels are going down around 1% a week due to increased Hydro generation. So as much as I love the interwebs, there's no point having fast internet if we have to power to turn anything on

I'll be coming over to Tassie in a week for a holiday, Alan so I'll have dig in my loose cable box to see if I have one long enough. I could probably rustle up a 5 port switch so your mates could hook in as a well if you like.

Wow! Im going there on the 10th -17th Feb for a holiday (Hobart and Lanceston) with my family...
My wife and I run a very busy web based business and Im hugely worried now. Ill be taking all my 3g/4g broadband modems to perhaps find some sort of wireless connection that will work. The places we are staying have wifi but who knows what state their ISPs will be in.

The original design capacity may have been 2.5G, or 2.5G per WAVELENGTH, but modern optics are quite impressive and its likely that Telstra would be able to get maybe a handful of 10G signals down each pair, and are possibly already doing so.

A friend who worked for Alcatel in the 2000's tells me that he was involved in a project to light 4x 2.5G on cable #2 in the early-mid 2000's, and Im sure they have much more than that lit today.

The initial article is not super clear. AFAIK other ISP's currently run a total of 2.5Gbps through the telstra pipes as redundancy. Of course there is way more over head in the pipes than that, each cable has like 4 cores. ( again what i was told by a telstra worker ) so they have whatever total capacity 4 cores allows ( over 400Gbps anyhow )

Right on the money. I did a speedtest.net to the internode server in Hobart and got 13 down / 1 up (pretty average)
Tested again to the internode in Melb.. 0.98 down (at best) 0.19 down at worst, didn't stick around to see my upload :(
Pro, Netflix still works.
Con, May 31 est finish :@

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